Various devices are implanted into the human body. Sometimes it is required to transmit motion into these devices for purposes of regulation or other reasons. One of the possible ways of accomplishing this requirement is by means of two magnets, one implanted, and a strong external one used for actuating the implanted one. The outside magnet, also termed a "driver" is generally a powerful electromagnet, while the implanted, driven one, is a small permanent magnet which follows the movement of the driver and thus performs the various tasks.
It is generally required that the movement of the implanted member be controlled in an accurate manner. This requires speed reduction means and locking means so as to maintain the driven member is a certain position after the driver has been removed and shut off. It is also required that a predetermined position of the driven member can be easily reached in an accurate manner.